Apparatus for producing fluorescent lamps

ABSTRACT

An apparatus for producing fluorescent lamps comprises an intermittently rotatable turret having a plurality of glass tube supporting arms extending radially from the turret. The apparatus is so arranged that a plurality of glass tubes supported from the supporting arms are simultaneously subjected to working operations such as heating, bending, evacuation, filling, sealing etc. at a plurality of stations in each of which a plurality of glass tubes are subjected to the same working operation to improve the productivity of the apparatus.

United States Patent Fujio et al. Oct. 7, 1975 [54] APPARATUS FORPRODUCING 2,772,134 11 1956 Mullan 316/32 FLUORESCENT LAMPS [75]Inventors: Hinomaru Fujio, Neyagawa; Primary Examiner-Roy Lake KazunoriFukunaga, Osaka; Assistant Examiner-James W. Davie Naoyuki Nakamura,Takatsuki, all Attorney, Agent, or Firm-Stevens, Davis, Miller & ofJapan Mosher [73] Assignee: Matsushita Electronics Corporation,

Osaka, Japan [57] ABSTRACT [22] Filed: Oct. 23, 1973 An apparatus forproducing fluorescent lamps com- [21] Appl' 408534 prises anintermittently rotatable turret having a plurality of glass tubesupporting arms extending radially [30] Foreign Application PriorityData from the turret. The apparatus is so arranged that a Dec. 29, 1972Japan 48-9619 plurality of glass tubes Supported from the Supportingarms are simultaneously subjected to working opera- 52] US. Cl 316/30;65/281 tions such as heating, bending, evacuation, filling, 51 int. (:1.HOlJ 9/38 sealing em at a plurality of stations in each of which a 58Field Of Search 316/27, 30, 31; 65/281 plurality of glass tubes areSubjected to the same working operation to improve the productivity ofthe [56] References Cited pp UNITED STATES PATENTS v 1/1950 Yoder et a1316/20 6 Claims, 4 Drawing Figures US. Patent Oct. 7,1975 Sheet 1 of 23,910,662

US. Patent Oct. 7,1975 Sheet 2 of2 3,910,662

FIG. 3

APPARATUS FOR PRODUCING FLUORESCENT LAMPS The present invention relatesto an improvement in an apparatus for producing fluorescent lamps and,particularly, annular or ring-like fluorescent lamps.

In the art of producing annular fluorescent lamps, there has been knownan exhausting machine comprising an intermittently rotatable turrethaving a plurality of glass tube supporting arms. The machine is soarranged that the turret is rotated intermittently or at a predeterminedinterval so that glass tubes supported from the supporting arms aresuccessively subjected to several kinds of working operations suchheating, bending, exhaustion, filling, sealing etc.

As an example, a prior art apparatus for producing annular fluorescentlamps conprises a turret having 24 supporting arms each having a head towhich a glass tube is removably connected. When the turret of the knownmachine is stopped at any one of predetermined stationary positions orstations, one of the 24 heads is operated to grip a glass tube, other 6heads support 6 glass tubes which are being pre-heated, other 4 headssupport 4 glass tubes which are being heated, another head supports aglass tube which is being bent, other 10 heads support 10 glass tubeswhich are being exhausted, another head supports a glass tube which isbeing filled and sealed and the remaining one head supports a glass tubewhich is being detached from the head.

In order to improvde the productivity or efficiency of such a knownmachine, i.e., to increase the number of fluorescent lamps produced bythe machine in a unit of time, it is usually attempted to shorten thetime required for the operation in each station of the machine. However,since there is a minimum time inevitably necessary for each of thenecessasry working operations such as the exhaustion of a tube, it isnecessary not only to minimize the time while a tube is stopped, i.e.,the time required for working the tube in each station but also toincrease the number of stations at which various working operations arecarried out. For example, assuming that a prior art machine is soarranged as to be stopped for 10 seconds at each of 10 stations at whichexhaustion is carried out, the machine has a total of lOO seconds forthe exhaustion. If it is intended to shorten the time for stoppage ateach station to 5 seconds so as to improve the efficiency of themachine, the machine will be required to have stations for theexhaustion. However, since there is a limit in the shortening of timerequired for the movement of each head from a station to a next one, theproductivity or efficiency of the machine cannot be increased inproportion to the increase in the number of heads.

In addition, it is impossible to simply shorten the time required for akind or kinds of working operations. For example, it is impossible toextremely shorten the time required for the bending of a glass tubebecause of a limit for the stress in glass tube caused by the operation.

For the reasons, there is an unavoidable limit for the improvement ofproductivity of thiskind of machine by way of shortening the time whilethe machine is stopped in each station.

It is an object of the present invention to provide an improvedapparatus for producing annular fluorescent lamps which is free from thedifficulty discussed above and which possesses an increased productivityor efficiency.

According to the present invention, there is provided an apparatus forproducing annular fluorescent lamps, comprising a turret which isintermittently rotated about its axis, a plurality of supporting armsmounted on said turret for rotation therewith and extending radiallyoutwardly therefrom, exhaustion heads on the outer ends of saidsupporting arms for holding and supporting a plurality of glass tubes,heating means, bending means and exhausting means on the path of travelof glass tubes, said apparatus being so arranged that glass tubessupported by two extension heads are simultaneously subjected to thesame kind of working operation. The above and other objects, featuresand advantages of the present invention will become apparent from thefollowing description with reference to the accompanying drawings.

DESCRIPTION or THE DRAWINGS FIG. 1 is a diagrammatic plan view of anembodiment of the apparatus of the present invention;

FIG. 2 is a plan view of a tube bender of the apparatus for bendingglass-tubes with a part of the tube bender being removed;

FIG. 3 is a side elevation of the tube bender with a part thereof beingremoved; and

FIG. 4 is a fragmentary diagramatical plan view of another embodiment ofthe apparatus of the present invention with parts of the embodimentbeing removed.

Referring first to FIG. 1 of the drawings, an embodiment of theapparatus according to the present invention comprises a turret B having28 tube supporting arms 1 extending radially outwardly therefrom. Eachof the arms 1 has a exhausting head 2 mounted thereon at the outer end.The exhausting head 2 is adapted to be detachably connected with anexhausting tube secured to an end of a linear tube of glass having acoating of phosphor on the inner wall of the tube and an electrodemounted on the tube at one end thereof so that the head 2 supports thetube and communicates the inner space thereof with a vacuum pump (notshown) through the exhausting tube. The arms 1 are adapted' to beintermittently rotated about the axis of the turret Bin a directionindicated by an arcuate arrow shown in FIG. 1 in such a manner that apair of exhausting heads 2 are successively moved through and paststations S1 through S14 disposed on a circular path of travel of theexhausting heads 2. When a pair of heads 2 are at the station S1, theheads are loaded with linear glass tubes which have not been exhausted.The glass tubes are gripped by the exhausting heads 2 at this station.At the stations S2 and S3 the glass tubes are preheated by a pre-heatingfurnace 17 which is so shaped and sized as to allow the glass tubes tobe moved through the furnace by the rotation of the turret B. At thestations S4 and S5 are provided heating furnaces l8 and 19 each having ahollow structure of a generally oval cross-section. Each of the heatingfurnaces l8 and 19 is formed of two sections which can be separatedapart from each other so that glass tubes can be moved into the furnace.When glass tubes are received in each of the furnaces 18 and 19, thefurnace is closed for the heating of the tubes to an elevatedtemperature. Glass tubes are filled with an inert gas while they arebeing moved through and past the stations S2 through S5 to avoidoxidization of the electrodes within the tubes.

At the station S6 linear glass tubes are shaped into circular or annularones by means of a tube bender disposed radially outwardly of thecircular path of the travel of the tubes through the station S6. Thebends 20 is chiefly comprised of a base plate 21, support 22 (both shownin FIG. 3) and a pair of pulleys 23 and 24. The plate 21 is movable inradial directions with respect to the circle of travel of glass tubes asindicated by a double-headed arrow in FIG. 1. The support 22 is locatedabove the base plate 21 and is movable up and down by a chain 54. Thepulleys 23 and 24 are mounted on one end of the support 22 as will bedescribed in more detail hereunder.

The apparatus of the present invention is advantageous in that twopulleys are mounted coaxially so that the tube bender is free fromunnecessary mechanical elements to enable the bender to be compact andsmall-sized. More specifically, the pulleys 23 and 24 are respectivelyformed of pairs of pulley halves 25 and 26 and 27 and 28, as shown inFIG. 2. Each pair of halves are axially movable with respect to oneanother into and out of mutual abutting engagement with each other tocomplete or divide a pulley. The four pulley halves 25, 26, 27 and 28are secured to axles 29, 30, 31 and 32, respectively, which in turn arejoumaled by bearings 33, 34 and 35, respectively, and are driven bygears 55, '36 and 37. The axles 29 through 32 are formed with splinesthrough which the axles are drivingly connected to the gears 55, 36 and37 but are axially slidably movable with respect to these gears.Particularly, the axle 31 is in the form of a tube having splined innerand outer surfaces. The axle 31 is drivingly connected to the axlethrough the splines on the inner surface of the axle 31 and on the outersurface of the axle 30 and is also drivingly connected to the gear 36through the spline on the outer surface of the axle 31 and a sprocket(not shown) on the gear 36. The axles 29 through 32 have secured theretowheels 38, 39, 40 and 41, respectively, having circumferentiallyextending grooves in which rollers on one ends of levers 42, 43, 44 andare rotatably received. These levers have intermediate portionspivotally mounted on a machine frame by means of pivot pins 46, 47, 48and 49, respectively. The other ends of the levers 42 and 43 arepivotally connected to a link means while the other ends of the levers44 and 45 are similarly connected to a second link means 51. The linkmeans 50 is movable toward and away from the pulley 23 by a hydraulicmechanism, not shown, so that the pair of the circumferentially groovedwheels 38 and 39 and the associated pulley halves 25 and 26 are axiallymovable toward and away from each other. The second link means is alsoactuated by a hydraulic mechanism, not shown, for a similar operation.Further details of the bender 20 will not be described herein and itwill be sufficient for the applicants to make a reference to US. Pat.No. 2,494,923 granted to J. Yoder et al. and disclosing method andapparatus for bending and exhausting tubular lamps.

In operation, a pair of non-exhausted linear glass tubes are gripped bya pair of exhausting heads 2 at the station S1 so that the glass tubesextend vertically. As the turret B of the apparatus is rotated, theexhausting heads are moved together with the gripped glass tubes to thestations S2 and S3 in which the glass tubes are pre-heated by thepre-heating furnace 17 from which the glass tubes are then moved to thestations S4 and S5 in which the glass tubes are further heated to theirsoftening temperature. When the heated glass tubes are moved to thestation S6, the tube bender 20 is moved radially inwardly of thecircular path of the travel of the glass tube. At this time, the support22 in its lowermost position and the pairs of pulley halves 25 and 26and 27 and 28 are both closed to complete the pulleys 23 and 24. Thelatter have tube-engaging pieces mounted on the peripheries thereof,each of the tube-engaging pieces being brought into engagement witheither a ring of a metal secured to a lower end of a glass tube or areduced lower end portion of the glass tube. Then the support 22 ismoved upwardly by the chain 54. The gears 55, 36 and 37 are rotated bythe meshing engagement between a rack 52 (shown in FIG. 3) and a pinion53 (shown in FIG. 2) so that the two heated glass tubes are bent aboutor wound on the pulleys 23 and 24, respectively. The upward movement ofthe support 22 is discontinued when the two glass tubes are completelywound on the pulleys 23 and 24. Then the link means 50 and 51 are movedaway from the pulleys 23 and 25 by the hydraulic mechanisms mentionedabove so that the pairs of pulley halves 25 and 26 and 27 and 28 aremoved apart from each other, respectively. At this time, the axles 29through 32 are slidably moved axially relative to the gears 55, 36 and37, respectively. Because the axle 31 is double-splined, as discussedabove, the axle 31 is required to advantageously have a short length forthin splines. For the reason, there is required a short distance betweenthe two pulleys 23 and 24. This advantageously enables the apparatus ofthe invention to be small-sized and made compact.

When the pairs of the pulley halves are separated apart, the tube bender20 is moved radially outwardly to its initial position and the glasstubes which have been formed into substantially annular shapes are movedto the next station S7. At the stations S7 and S8, exhausting tubes onends of the annular glass tubes are connected to predetermined terminalsof a head of a suction machine. The glass tubes are then moved to andthrough the stations 9 through 12 in which the glass tubes areexhausted. The glass tubes are then moved to the station 13 in which theexhausted glass tubes are filled with drops of mercury and a quantity ofa rare gas such as argon gas. The glass tubes are finally moved to thestation S14 in which the suction tubes on the glass tubes are sealed andthe glass tubes are removed from the apparatus.

The apparatus of the embodiment shown in FIG. 1 of the drawings has anincreased number of exhausting heads than those of prior art apparatusbecause, with the apparatus described and illustrated above, two glasstubes are subjected to simultaneous working operations at each of theheating, bending, exhaustion, filling, sealing and other stations. Theapparatus is required to have a base of a large diameter for theappropriate indexing'of tube supporting arms and strength of machinestructure. This inevitably causes the entire apparatus, including thesupport arms, to have a large diameter, with a resultant problem thatthe inertia of the rotation of the base is increased to cause heavyvibration of the apparatus which adversely affects the production sameworking operation define between them an angle :1 which is less than anangle [3 between the arm lb and an adjacent arm or an angle [3 betweenthe arm 1b and an adjacent arm la so that unequal angles are providedbetween the respective arms. in the embodiment of FIG. 4, the arms areshown as being arranged such that a, a 04 [3, B

For example, assuming that the apparatus shown in FIG. 4 has (28 heads(28 assemblies of exhausting heads and support arms), the apparatus isallowed to have smaller angles to be defined between 14 arms (7 pairs ofarms). Thus, the turret Ba is required to have a smaller diameter so asto satisfy the requirement for the indexing of the support arms on thebase. Thus, the entire apparatus, including the support arms, can have areduced diameter with a resultant advantage that the apparatus if freefrom the increase in the inertia and in resultant vibration of theapparatus which increase would otherwise be caused when the apparatus isrotated. Thus, the apparatus of this embodiment of the invention isadvantageously freed from the problem discussed in connection with theembodiment of the invention shown in FIG. 1.

As having been described above, the present invention provides anapparatus for producing fluorescent lamps which is compact andsmall-sized and capable of producing fluorescent lamps at an improvedproductivity while the improvement in the productivity does notadversely effect the quality of the products. With the apparatus of thepresent invention, moreover, a heated and bent glass tube can be given alonger time for the annealing of the tube than by a machine which has asimply increased number of tube supporting arms with a resultantadvantage that stress in the bent glass tube can be fully removed.Furthermore, the apparatus of the present invention has a shortened timerequired for the movement of a bent glass tube to the exhaustionstations. The movement in a shortened time enables the glass tube to besubjected to exhaustion for a prolonged time with a resultant advantagethat the glass tube is fully exhausted, which contributes to theincrease in the quality of products.

What we claim is:

1. An apparatus for producing annular fluorescent lamps comprising:

a turret which is intermittently rotated about its axis,

a plurality of supporting arms mounted on said turret for rotationtherewith and extending radially outwardly therefrom,

exhaustion heads on the outer ends of said supporting arm for holdingand supporting a plurality of glass tubes,

a plurality of work stations on the path of travel of the glass tubes, afirst work station comprising a heating means, a second work stationcomprising a bending means for bending two next adjacent glass tubessupported by two next adjacent exhaustion heads substantiallysimultaneously, and a third work station comprising an exhausting means,and

means interconnecting said first and second bending means for effectingthe substantially simultaneous operation thereof.

2. An apparatus as claimed in claim 1, in which said first bendingmeanscomprises a first pulley, said second bending means comprises asecond pulley, and said first and second pulleys are coaxially arranged.

3. An apparatus as claimed in claim 2, in which each of said coaxialpulleys is formed of a pair of axially separable pulley halves, theadjacent pulley halves of said pulleys being connected by spline meansso that said adjacent pulley halves are rotatable together but axiallyrelatively movable toward and away from each other.

4. An apparatus as claimed in claim 1, wherein said heating meanscomprises means for heating two next adjacent glass tubes supported bytwo next adjacent exhaustion heads substantially simultaneously.

5. An apparatus as claimed in claim 1, wherein said exhaustion meanscomprises means for exhausting two next adjacent glass tubes supportedby two next adjacent exhaustion heads substantially simultaneously.

6. An apparatus as claimed in claim 1, in which each pair of supportingarms for supporting a pair of glass tubes to be simultaneously subjectedto the same working operation define therebetween an angle which is lessthan another angle defined between one of said pair of supporting armsand a next adjacent arm.

1. An apparatus for producing annular fluorescent lamps comprising: aturret which is intermittently rotated about its axis, a plurality ofsupporting arms mounted on said turret for rotation therewith andextending radially outwardly therefrom, exhaustion heads on the outerends of said supporting arm for holding and supporting a plurality ofglass tubes, a plurality of work stations on the path of travel of theglass tubes, a first work station comprising a heating means, a secondwork station comprising a bending means for bending two next adjacentglass tubes supported by two next adjacent exhaustion headssubstantially simultaneously, and a third work station comprising anexhausting means, and means interconnecting said first and secondbending means for effecting the substantially simultaneous operationthereof.
 2. An apparatus as claimed in claim 1, in which said firstbending means comprises a first pulley, said second bending meanscomprises a second pulley, and said first and second pulleys arecoaxially arranged.
 3. An apparatus as claimed in claim 2, in which eachof said coaxial pulleys is formed of a pair of axially separable pulleyhalves, the adjacent pulley halves of said pulleys being connected byspline means so that said adjacent pulley halves are rotatable togetherbut axially relatively movable toward and away from each other.
 4. Anapparatus as claimed in claim 1, wherein said heating means comprisesmeans for heating two next adjacent glass tubes supported by two nextadjacent exhaustion heads substantially simultaneously.
 5. An apparatusas claimed in claim 1, wherein said exhaustion means comprises means forexhausting two next adjacent glass tubes supported by two next adjacentexhaustion heads substantially simultaneously.
 6. An apparatus asclaimed in claim 1, in which each pair of supporting arms for supportinga pair of glass tubes to be simultaneously subjected to the same workingoperation define therebetween an angle which is less than another angledefined between one of said pair of supporting arms and a next adjacentarm.